1. Field of the Invention
The present invention relates to a device for magnetically treating fluids flowing through a conduit and more particularly the invention relates to a device for magnetically treating crude oil as it is being conveyed from an oil bearing structure in the ground to the surface to prevent the precipitation of paraffin in the conduit.
2. Description of the Prior Art
For at least the past twenty-five years, it has been known that the flow or travel of fluid through a conduit, and the fluid itself, can be influenced by the presence of a magnetic field in the conduit in which the fluid moves. For example, water being supplied to power plants, boilers, and other industrial water systems, can be treated by a magnetic field which effectively reduces the problems associated with the formation of scale and other precipitates in the water system. After treatment with a magnetic field, the water does not produce a hard scale on the walls of the conduits of the water system. Rather, a loose sludge is formed which will settle to the bottom of the system. The sludge can easily be removed or flushed from the water system. The interior of the piping system, therefore, does not require a more radical cleaning to maintain efficient operability of the system.
Gasoline being supplied as a fuel to automobile engines may be treated magnetically with a resulting increase in fuel efficiency and a reduction in the accumulation of various hydrocarbon deposits in the fuel carburation or injection system. The magnetic treatment, which may be accomplished by a rather simple and inexpensive magnetic device, results in increased fuel economy and decreased air pollution through the reduction of engine emissions and more complete fuel combustion.
While much is known about how the application of a magnetic field to a fluid flowing through a conduit affects the fluid, knowledge about all factors which contribute to the influence of the magnetic field is incomplete. Several theories have been proposed. Those skilled in the art, however, generally agree that the application of a sufficiently strong magnetic field to a flowing fluid will reduce the precipitation of material in solution in the fluid. In many cases, precipitation is unwanted and magnetic treatment provides desirable results.
In the oil production industry, paraffin precipitatation from crude oil as the crude oil flows from an oil bearing formation through production or supply tubing can present a serious problem. The paraffin precipitate will form deposits in the delivery system and impede the oil flow.
Frequently natural pressure in an oil bearing formation is too low to raise the oil to the ground from the oil bearing formation. Pumps are commonly employed to move the crude oil to the surface. The pumps, which are located underground, are operated by a pump rod driven by a prime mover. The pump rod extends through the production tubing between the prime mover and the pump.
The paraffin deposits, which commonly occur, are normally located at a position in the supply tubing just above the point where the crude oil being pumped reaches the cloud point of the oil. The cloud point, defined by ASTM standards, is, broadly, that temperature at which paraffin first begins to precipitate in the crude oil.
Paraffin deposits in the supply tubing will eventually clog the tubing or restrict movement of the pump rod or both. When oil flow through the system is restricted it becomes necessary to clean the system. To obviate this problem, it is common to employ periodic preventative cleaning procedures so that production is not unduly interrupted.
These preventative procedures, while necessary, are costly and undesirable. First, cleaning requires that the well be shut down during cleaning, and production time is lost. Second, the cleaning procedures require the use of capital equipment and labor and, therefore, involves nonproductive expense. Third, hazardous chemicals are commonly used in the cleaning procedures and a negative impact on the environment is possible. All of these factors contribute to higher oil production costs.
Brine, which promotes corrosion, other corrosive materials, and scales of various types, are also present in an oil well environment. The magnetic treatment of oil, as it flows through a supply tube can substantially reduce the formation of scales, the corrosion promoting property of the brine and the corrosive effect of other materials in the oil.
It has been theorized that the paraffin precipitation problem in oil wells results because paraffin is naturally present in solution in many crude oil formations. As the crude oil is transmitted from the oil bearing formation to the surface, pressure and temperature changes occur. If the cloud point is reached, paraffin will precipitate from the crude oil as it moves through the supply tubing. The paraffin formation and deposition occur because of chemical, mechanical, and electrical effects. It is also theorized that paraffin forms by chemical reaction in the crude oil while the crude oil moves through supply tubing by changes in pressure and temperature.
The movement of crude oil, through either the oil bearing formation in the earth or the tubing which delivers the crude to the surface, will create an electrical potential. It is believed that this electrical potential contributes to the formation and precipitation of paraffin. Regardless of the exact mechanisms involved, whether they be mechanical, chemical or electrical, in some environments, paraffin does accumulate in oil supply tubing. This accumulation of paraffin in the supply tubing is a problem which must be addressed. Further, it is known that the treatment of crude oil as it flows through supply tubing with a magnetic field will substantially reduce and, in some instances, totally eliminate the precipitation, deposition, and accumulation of paraffin in oil well supply tubing.
The prior art has addressed the precipitation problem in general, and several examples of proposed solutions are known in the art. One example is Weisenbarger U.S. Pat. No. 4,995,425. This patent discloses a magnetic fluid treatment device having a pair of elements containing permanent magnets mounted in housing members. The housing members are placed around a fluid conduit to direct the magnetic field flux to the flowing fluid. This reference is primarily concerned with the magnetic treatment of water conduits such as the plumbing supply system of a residential construction. However, the reference does indicate that the device of the disclosure can be used in an oil well environment.
Hertzog, U.S. Pat. No. 4,946,590 discloses a magnetic water treatment device which is intended to be clamped upon domestic plumbing supply systems. The device shown in this disclosure is in many ways similar to the Weisenbarger device. The differences reside in the arrangement of the magnets used in the construction.
O'Meara, Jr., U.S. Pat. Nos. 4,289,621; 4,417,984; and 4,564,448 each shows various devices for treating fluids flowing through a conduit with a magnetic field to reduce the formation of precipitates from material in solution in the fluid. Each of these devices includes a magnet member that is mounted inside the tubing through which the fluid flows.
Each of the devices of the prior art, as represented by the references noted, includes drawbacks, particularly if such devices are to be used in an oil well environment. For example, the O'Meara, Jr. references each disclose structures having magnets mounted inside a fluid conduit. Such a structure is totally unsatisfactory or unsuitable for use in an oil well. The placement of magnetic means in the path of oil flow will obstruct the oil movement. Also, pump rod operation will be impeded in those oil wells having pumps.
Weisenbarger and Hertzog also disclose structures which would be unsuitable for use in an oil well environment. Both disclosures involve devices which are clamped around the exterior of the fluid conduit. Oil well equipment is subjected to heavy wear, tear and abuse from the various forces, pressures, and other actions which typically occur in the drilling, installation and operation of an oil well. This abuse is exacerbated where the desired location for magnetic treatment is located a substantial distance below the surface of the earth.
Accordingly, there are numerous oil wells in existence in which paraffin buildup presents a problem, and a serious need exists for a device which will either substantially reduce or eliminate the paraffin buildup problem. Several characteristics of such a device are necessary when the device is to be used in an oil well environment. For example, the device must be rugged and capable of withstanding the abuse which is inevitably encountered in the oil well industry. Secondly, the device should not interfere with the flow of crude oil through the supply tubing. To do so would contribute to the problem the device is designed to eliminate. Third, the device should be of a character which is compatible with equipment which is normally present in the oil drilling and supply industry. Additionally, the treatment equipment should be cost effective so that its employment and use do not unduly increase the net maintenance costs associated with a typical oil well.
Ideally, therefore, the cost of including magnetic treatment equipment should be equal to or exceeded by the savings resulting from the employment and use of the equipment.
Accordingly, it is a primary object of the present invention to provide a magnetic treatment device for reducing paraffin buildup in an oil well, which device becomes an integral part of the supply tubing or conduit, and does not interfere with the flow of crude oil passing through the conduit.
It is also an object of the present invention to provide a magnetic treatment device for oil wells which is capable of being mounted in and become a part of the string of pipe which forms the oil supply tubing or conduit of an oil well.
It is a further object of the present invention to provide a magnetic treatment device for oil well use which is an integral part of the oil supply system.
It is a further object of the present invention to provide a magnetic treatment device for oil well use which either substantially decreases or eliminates the precipitation of paraffin in the crude oil supply system of the oil well.
It is likewise an object of the present invention to provide a magnetic treatment device for oil well use in which the device may be placed at any position in the string of pipe which forms the oil supply tube or conduit of a oil well crude oil supply system, which location is normally determinted by the position of the "cloud point" of the oil flowing through the crude oil supply system.
It is an additional object of the present invention to provide a magnetic treatment device for oil well use which is mounted within the oil well casing that normally forms a part of an oil well crude oil supply system.